CSS bloat is there also, perhaps not as big a deal. I think that complexity is the main enemy (both JS and CSS and React and npm …) or over on the WordPress plugin morass. I like that the OP is aiming for a simpler world, kind of like the HTMX and Pico CSS ideas that I currently prefer.
52K of CSS should be an opportunity for optimization but you're right, we're so far gone on javascript we should really focus on the mountains before the molehills.
That's like asking any other software dev to "say no" to letting other programs run concurrent with their own. It's just not within scope and any attempts to have your program behave this way will be impossible to maintain.
If you're a business that wants to inject ads without anyone getting in the way, all you have to do is host the pages somewhere the dev can't touch. This would likely be a CDN or similar for a multitude of other good reasons. So the content security policy is now only configurable by the admin who really doesn't give a shit and doesn't even know what's being hosted on there.
Tree shaking and bloat are different concerns. And, technically, is tailwind tree shaking? I thought they only built styles that the compiler could find being used rather than removing styles the compiler couldn't find being used.
Tree shaking is actually a sign of bloat. It is a tool on top of a bloated mess, to fix that mess. It would be better not to make a mess in the first place.
